Former U.N. Secretary-General Kofi Annan says it is essential that leaders at the G8 plus five summit in Germany this week forge a common strategy on climate change. As Daniel Schearf reports from Beijing, the former head of the United Nations says both developed countries, and fast-developing nations such as China, share responsibility for slowing the effects of global warming.

Kofi Annan says climate change is not only a threat to the global environment, but also to world peace and security, as worsening environmental conditions could lead to mass migrations.

Speaking in Beijing at the annual meeting of the World Wildlife Fund, Mr. Annan said it is essential that a common global climate strategy be advanced at this week's meeting of the G8 industrialized nations and five leading developing countries.

"The time for recriminations and passing the buck is over," said Mr. Annan. "International discussions on action to curb climate change need to be put back on track, with clarity on what needs to be done, when, and by whom."

Mr. Annan says global economic leaders must accept historic responsibility for the bulk of the gas emissions that are thought to cause global warming. He says the United States, the largest emitter of such greenhouse gases, should take the lead in responding to climate change.

But he also says an effective global strategy will fail without more action from fast-developing nations such as India, Brazil, and China.

China, in particular, is expected to overtake the United States as the largest emitter of carbon dioxide, believed to be a leading cause of climate change, as early as this year.

"These countries will account for the bulk of future emissions, and have a major responsibility in managing the future," said Mr. Annan. "Without their commitment, motivated by substantial transfers of capital and technology, effective and fair global action will remain out of reach."

Annan says poor countries, many of them in Africa, will suffer disproportionately from the weather changing effects of climate change, as they are most dependent on the weather-sensitive agriculture, fishing, and forestry industries.

He says Beijing's close engagement with African governments means China could influence how Africa develops and responds to the threat of climate change.

"With these new partnerships in Africa and elsewhere, China has an important opportunity and responsibility to influence the management of natural resources and to shape new industries and new markets," said the former U.N. chief.

China announced plans this week to combat climate change, but not at the expense of economic expansion, and it refuses to be tied to specific limits on gas emissions.